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Ram-Air Intake question

Mercury940

New member
Joined
Jun 5, 2007
Location
Lexington, KY
Hey, I have a 91' 944 Turbo and I saw the article about adding a ram air intake to a 740 and had considered sticking one on my 940T. What size pipe would you all recommend to get best performance? As well, I was going to rout the hose for the ram-air under the air dam or through the vent on the air dam, and wanted someones opinion on installing an air bypass valve like an AEM one on there to prevent water from getting in to the intake. Are there any other good ways to keep water out? As well what is my best bet about putting a better exhaust system on my car?

Thanks in advance,
Robert
 
Hey, I have a 91' 944 Turbo and I saw the article about adding a ram air intake to a 740 and had considered sticking one on my 940T. What size pipe would you all recommend to get best performance? As well, I was going to rout the hose for the ram-air under the air dam or through the vent on the air dam, and wanted someones opinion on installing an air bypass valve like an AEM one on there to prevent water from getting in to the intake. Are there any other good ways to keep water out? As well what is my best bet about putting a better exhaust system on my car?

Thanks in advance,
Robert

This is a hotly contested topic here where a lot of people have had their opinions influenced (positively or negatively) by stupid stores selling gimmicks that they call ram air and the "The Fast and the Furious". If you really want to understand how a good ram air system can work on a car, take a look at how the inlet tracts on motorcycles are designed. Here are some things to note....

1) Huge inlet in the front (not somewhere in the engine! That's not a ram, short ram, or cold air intake. That's crap!)
2) A HUGE airbox
3) Sealed

You have to remember that these things don't generate significant boost (Don't know if you knew that or not. :oops:). But they can (if well designed) provide a slight over pressure effect. Slight, but not much at all. If you've ever driven your car around and noticed how well it ran in the region of 0 in / 0 psi, you can get an idea of how atmospheric motors benefit from this.

What's still hotly contested around here is whether or not this is worth it on a turbo car. I say yes. The reason being that when your turbo really starts to spin, it's going to need huge amounts of air at the inlet to generate that 20psi you and I both know you want. ;-) If the inlet tract upstream of the turbine is poorly designed, how much harder does the compressor have to work to generate that 20psi? Especially considering that in a non-ram air setup, the inlet tract essentially becomes a vacum cleaner tube right?

A well designed inlet tract will help feed that beast.

As for how big you should make the pipe, I don't know. I'm using two 3" pipes to feed an airbox upstream of my MAF.

And if you are worried about water, just don't have the inlet so low. Some people cut holes through their bumper. Hint.... hint..... :-D

If you still at risk or getting water in then, you've obviously ignored warnings and common sense and ventured out into a storm that's laying serious waste to your surroundings.

Cheers
 
This is a hotly contested topic here where a lot of people have had their opinions influenced (positively or negatively) by stupid stores selling gimmicks that they call ram air and the "The Fast and the Furious". If you really want to understand how a good ram air system can work on a car, take a look at how the inlet tracts on motorcycles are designed. Here are some things to note....

1) Huge inlet in the front (not somewhere in the engine! That's not a ram, short ram, or cold air intake. That's crap!)
2) A HUGE airbox
3) Sealed

You have to remember that these things don't generate significant boost (Don't know if you knew that or not. :oops:). But they can (if well designed) provide a slight over pressure effect. Slight, but not much at all. If you've ever driven your car around and noticed how well it ran in the region of 0 in / 0 psi, you can get an idea of how atmospheric motors benefit from this.

What's still hotly contested around here is whether or not this is worth it on a turbo car. I say yes. The reason being that when your turbo really starts to spin, it's going to need huge amounts of air at the inlet to generate that 20psi you and I both know you want. ;-) If the inlet tract upstream of the turbine is poorly designed, how much harder does the compressor have to work to generate that 20psi? Especially considering that in a non-ram air setup, the inlet tract essentially becomes a vacum cleaner tube right?

A well designed inlet tract will help feed that beast.

As for how big you should make the pipe, I don't know. I'm using two 3" pipes to feed an airbox upstream of my MAF.

And if you are worried about water, just don't have the inlet so low. Some people cut holes through their bumper. Hint.... hint..... :-D


If you still at risk or getting water in then, you've obviously ignored warnings and common sense and ventured out into a storm that's laying serious waste to your surroundings.

Cheers

First, should I be working on expanding the piping upstream the airbox? (By the way I think the engine is the "K" series B230FT with a Mitsubishi(?) turbo) As well I was thinking about using 2.5" to 3" pipe for the cold air intake, so it sounds like I am close to on target. Second, my main issue with cutting a couple holes in the bumper is that I am trying to keep the aesthetic modification to a minimum, and cutting holes in the bumper doesn't quite seem the most appealing thing to me, hence running under the air dam. As well would it make sense to just run it somewhere else like near the fenders or something?

Robert
 
Gudday, I'm not too knowledgable on the subject but I've recently been doing some reading on this sort of stuff. I wish I had more practical knowledge but it's been mainly reading.

The posts previously have some damn good info but there are some more little things to take notes of.

If you want to really get a ram air system going you're going to have to do some tests with gauges about where on the car you have the most air pressure. This is usually on the front of the car and after the leading edge on the bonnet but each car is radically different and needs testing. This is something I'm planning on doing in the upcoming year. The reason for this is that if you site the air intake in a low pressure area - using a bonnet vent as an example - you can actually have air sucked out if it isn't all sealed.

Whatever system you have you will need to seal it. If it's the standard system you're just playing with the air intake hose into the airbox and you won't have many issues. If you replace the airbox and want a pod filter or similar you may want - for best results - to have the pod filter actually enclosed in a custom airbox with feeder pipes leading into it. This is due to air always taking the flow that's easiest and even if you have the exit of a ram-air pipe pointing directly to the pod filter most of the air will actually flow past the filter. Some will go in but you won't be getting the maximum flow possible. By boxing it you also get the escaping air building pressure in the box which will then force air into the filter. It's the same theory about boxing in a radiator/intercooler and the cooling fans to stop air bypassing the radiator.

If you don't want to go to the trouble of testing for high pressure areas you'll probably want to guess where a high pressure area is going to be. It's kind of obvious for a 740 I guess, the bumper or the headlights. Any lower and you start to loose air under the car, any higher and you need a bonnet scoop around a foot back from the leading edge. Perhaps a good option is to create a collector box behind the grill, covering up a bit of the intercooler/radiator. If you don't want to do that you should look at a bell mouth on the end of the pipe to help get air into the pipe - there's quite a bit of information about it on the net.

I'm not sure about the fenders but I think I read somewhere that fenders weren't a fantastic place, a good area for getting dirt and grit into the system and I don't think it's a high pressure area - don't quote me though! lol.

I guess just remember that you need a sealed system with a stream of cold air coming from a high pressure area and it should soundly beat the stocker system or a pod filter sitting in the engine bay.

Some sources: Angus has a good airbox collector on his 242 that would be worth a look. Ash has a pipe leading from a collector in the chin spoiler to the airbox but from what I can gather the main airbox performance gains he gets is from the low profile bonnet scoop. I have a chin spoiler shallow collector done by Ash and his Dad, Neil which was a good improvement over stock, especially when the H cam comes in and the car is near or over 80kph. The guys at www.autospeed.com have done a lot of testing on different cars and different setups and has been the bulk of my reading, great site and well worth some dough.
 
First, should I be working on expanding the piping upstream the airbox? (By the way I think the engine is the "K" series B230FT with a Mitsubishi(?) turbo) As well I was thinking about using 2.5" to 3" pipe for the cold air intake, so it sounds like I am close to on target. Second, my main issue with cutting a couple holes in the bumper is that I am trying to keep the aesthetic modification to a minimum, and cutting holes in the bumper doesn't quite seem the most appealing thing to me, hence running under the air dam. As well would it make sense to just run it somewhere else like near the fenders or something?

Robert


some people have cut a hole in the engine bay side of the fender and then fed a pipe into the hole, and stuck a filter on the end of it as seen here

http://www.pbase.com/dkauer744/image/39121284

not sure how the 940's are designed as far as where you could cut a hole that wouldn't damage stuff, but that sort of design would get you some air from outside the engine bay without totally jerry rigging a vacuum hose to the air dam.

honestly, i doubt you'll get much gain from having a "cold air intake" or a "ram air" especially on a turbo application. if you want to chill the air off that goes into the motor, try to figure out how to fit an all aluminum intercooler into the car, way better results. don't make the mistake of ruining what volvo did from the factory only to end up with something that looks home made(in a bad way) and doesn't really do anything to improve the workings of the car, leave that to the kids with cheap jap stuff
 
Keep the factory air box and run about 3 inch flex pipe down to the tow flap, seal the box, leave factory filter, don't have to worry about water.
 
some people have cut a hole in the engine bay side of the fender and then fed a pipe into the hole, and stuck a filter on the end of it as seen here

http://www.pbase.com/dkauer744/image/39121284
That's the area I'm going through on my 240. It drops into a region in front of the front right wheel well. That's a good area for an airbox. If i'm not mistaken, Doug just left a filter there on the end of the tube.

honestly, i doubt you'll get much gain from having a "cold air intake" or a "ram air" especially on a turbo application.

Mercury940: See what I mean?

if you want to chill the air off that goes into the motor, try to figure out how to fit an all aluminum intercooler into the car, way better results.

This isn't about chilling the air going into the motor. On a turbo car, it's about improving the efficiency of the inlet tract (getting as much air as possible) upstream of the compressor only.
 
First, should I be working on expanding the piping upstream the airbox? (By the way I think the engine is the "K" series B230FT with a Mitsubishi(?) turbo) As well I was thinking about using 2.5" to 3" pipe for the cold air intake, so it sounds like I am close to on target. Second, my main issue with cutting a couple holes in the bumper is that I am trying to keep the aesthetic modification to a minimum, and cutting holes in the bumper doesn't quite seem the most appealing thing to me, hence running under the air dam. As well would it make sense to just run it somewhere else like near the fenders or something?

Robert

How much have you done to the car to heretofore?
 
How much have you done to the car to heretofore?

As far as performance mods go, I haven't done any to this car yet. I get from the gist of some of the other posts perhaps ram-air might not be the way to go with my 940. As far as an intercooler upgrade what would you all recommend that would be good for the car? My dad has an old Turbodiesel Isuzu NPR that he about to do an engine swap on and may be disposing of the intercooler on it. Would the NPR intercooler be any better than what I already have? Second, from a couple posts I'm also getting that I might want to change the airbox? Is there another car that I could strip one out of thats better or should I leave this alone or what? Or maybe I am going in the complete wrong direction and should try something else for a mod.

Thanks in advance,
Robert
 
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pic of my setup (still need to fit a choke cable or motor to it)
wODcxMDY5NnM0MTNkZmQzMXk1NDE%3D.jpg

wODcxMDcwNnM0MTNkZmQzMXk1NDE%3D.jpg

if you notice the gray thing on the intake pipe. its a aem bypass in case water gets sucked up (i do put the plate on in the rain). basically a duct from the hardware store to seal the backside, no measurable boost, but breathes very well.
fyi, your pcv system will not like this too much. i ran with a smallet system for years w/o issue , but keep an eye on it.
 
I get from the gist of some of the other posts perhaps ram-air might not be the way to go with my 940.

I think it depends on how much performance you are after. There are certainly easier and more effective things to do. Cam, Turbo, exhaust, etc.....

OTOH, if you are really going gung ho, I think that should be on the list.

Look at a better turbo, exhaust, cam, and chips. With the right stuff, some guys are making north of 300hp without even doing any headwork. ;-)
 
I think it depends on how much performance you are after. There are certainly easier and more effective things to do. Cam, Turbo, exhaust, etc.....

OTOH, if you are really going gung ho, I think that should be on the list.

Look at a better turbo, exhaust, cam, and chips. With the right stuff, some guys are making north of 300hp without even doing any headwork. ;-)

Perhaps. Ram-Air just looked good because it was cheap, and my budget is fairly tight, however I am willing to look at something else. I almost hesitate to stick a bigger turbo on there because from what I hear pushing a lot more pressure to the engine means higher risk of detonation (I usually don't put any more than regular unleaded in it, so I worry about it), and might mean I cut some of the life out of the engine, although I could be wrong there. It seems maybe sticking a more efficient intercooler in there may be the way to go. I had looked at one off an NPR, but my dad probably won't let me have the one off of his NPR, and the Isuzu truck parts are usually expensive. Are there any other turbo cars with better intercoolers to be looking for at the pick-n-pull, that I might be able to use? As well what would be the best way to enlarge the exhaust for performance on it? Finally if anyone could point me in the direction of who is selling good chips for a 940T, it would be much appreciated.

Thanks in advance,
Robert
 
Now you're gonna get the ol' "use the search feature." All that info is out there in old posts. But here's a few answers:

The NPR is really one of the best drop-ins, and they can be had for less than $200 if you're patient and look around. There's been talk lately of the eBay bar-and-plate intercoolers that are advertised for cheap. Apparently they're quite good, but may require some cutting to fit.

A bigger turbo and or even just higher boost probably will require higher octane gas, but you have to pay to play. It won't blow up your engine if you're cautious.

Exhaust options.... for a turbo car, you want a 3" system from turbo to tailpipe, ideally. It's a good size for performance, and you shouldn't ever need larger, practically speaking. You'll have to get it custom made unless you want to pay big money for a system from Europe. However, a competent local custom exhaust shop ought to be able to do it. You'll want, I'd say, at the very least a glasspack and a Dynomax round muffler to keep the noise down. That's the setup on one of my cars, and it flows well, but it's also pretty quiet. Lots of opinions to search for on this board about what mufflers are best.

Fred sells chips. Check in the for-sale section... maybe in the group-buys subsection? Can't remember. I can't remember Fred's actual username either. But his chips would be a good buy.

Also consider a camshaft. Search for the CK-1. It's a new one made by a board member and it's reasonably priced. Also could try IPD's turbo camshaft. Both would be improvements.

Aaron
 
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